Solve for $p$ : $p + 7 = 25$
Solution: Subtract $7$ from both sides: $ \begin{eqnarray} \\ p + 7 &=& 25 \\ \\ {-7} && {-7} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{7 + p} &\hphantom{=}& \hphantom{25} \\ p &=& 25 {- 7} \\ \end{eqnarray} $ Simplify. $ p = 18$